1. Field of the Invention
The present invention relates to a signal processing method and a signal processing circuit adapted to a processing for converting an input signal.
2. Description of the Related Art
There has been conventionally proposed, as a method for converting a gamma characteristic (γ-characteristic) of an input image, a method disclosed in Japanese Patent Application Laid-Open No. 3-126377 and Japanese Patent No. 2512562.
With this method, the number of histograms corresponding to one image plane of the input image is counted, the histograms are subjected to a limit processing, a constant addition processing, and the like, and a cumulative histogram is calculated.
To use the cumulative histogram thus calculated as a gamma table, the cumulative histogram is normalized (scaled) so that a maximum value of the cumulative histogram is a maximum output of the gamma table.